Humidifier

ABSTRACT

A portable humidifier including an evaporator pan adapted to be mounted in the plenum of a furnace, a heating element in the evaporator pan connected to the furnace motor circuit, a reservoir mounted at a point remote from the evaporator pan and at the same level, a conduit connecting the reservoir to the evaporator, a source of water connected to the reservoir through a restricted conduit, a solenoid actuated control valve connected to control the flow of water through the restricted conduit and a double acting mercury switch mounted on a float in the reservoir to control the operation of the solenoid valve and to disable the heating element when the water in the evaporator pan drops below the heating element.

[ 51 May 23, 1972 HUMIDIFIER Herbert W. Radtke, 3755 South 20th Street, Milwaukee, Wis. 53221 [72] Inventor:

[22] Filed: May 5, 1971 [21] Appl. No.: 140,599

Related US. Application Data [63] Continuation of Ser. No. 5,628, Jan. 26, 1970, abandoned, Continuation-impart of Ser. No. 868,501, Oct. 22, 1969, abandoned.

Kellogg l26/l 13 Fazio ..2l9/272 X Primary Examiner-Charles J Myhre Attomey-Ronald E. Barry and James E. Nilles [57] ABSTRACT A portable humidifier including an evaporator pan adapted to be mounted in the plenum of a furnace, a heating element in the evaporator pan connected to the furnace motor circuit, a reservoir mounted at a point remote from the evaporator pan and at the same level, a conduit connecting the reservoir to the evaporator, a source of water connected to the reservoir through a restricted conduit, a solenoid actuated control valve connected to control the flow of water through the restricted conduit and a double acting mercury switch mounted on a float in the reservoir to control the operation of the solenoid valve and to disable the heating element when the water in the evaporator pan drops below the heating element.

8 Claims, 6 Drawing Figures RELATED APPLICATION This application is a continuation of application Ser. No. 5,628 filed Jan. 26, 1970 which in turn is a continuation-inpart of application Ser. No. 868,501 filed Oct. 22, 1969, and both being now abandoned.

BACKGROUND OF THE INVENTION Humidifiers for central hot air systems generally are permanently installed in the plenum of the furnace. All of the operating parts of the humidifier are combined into a single unit and all of the electrical and water connections are made 1 5 SUMMARY OF THE INVENTION The humidifier disclosed herein is readily adaptable to the plenum of any central hot air heating system and is not affected by the accumulation of deposits or liming which normally occurs in the evaporating system. This is accomplished by mounting only the evaporating pan in the plenum of the furnace. Evaporation of water is enhanced by a heating element mountedwithin the pan. A water level control assembly is mounted at a point remote from the furnace and includes a reservoir mounted at a the same level as the evaporator pan. The level of water in the reservoir is controlled by a double throw mercury switch mounted on a float in the reservoir. The mercury switch responds to the movement of the float to control the circuit to the heating element and the circuit to a solenoid actuated water valve. The mercury switch causes a delay I in the refilling of the reservoir by allowing the water in the reservoir to drop to a predetermined low water level before actuating the solenoid controlled valve. Water is then admitted to the reservoir until it rises to the high water'level before closing the water valve. Water noise is thereby eliminated or reduced since water only flows when the pan is being refilled and not continually as in prior systems.

I In an alternate embodiment of the invention the double throw mercury switch is controlled by a water level sensor located in the evaporating pan. The signal from the sensor is used to control the position of the mercury switch by a solenoid mechanically linked to the mercury switch. This arrangement also provides for a delay in refilling the evaporator pan and thereby eliminates continuous water noise.

7 Other objects and advantages will become apparent from the following description when read in connection with the accompanying drawing.

THE DRAWINGS FIG. 1 is a perspective view of the humidifier of this invention including a schematic showing of the electric circuit for operating the humidifier;

FIG. 2 is a view of the control assembly for the humidifier showing the mercury switch in the high water level position;

FIG. 3 is a view of the control assembly for the humidifier showing the mercury switch in the low water level position;

FIG. 4 is a perspective view of an alternate embodiment of the present invention including a schematic showing of the electric circuit;

FIG. 5 is a view of the mercury switch in the high water level position; and

FIG. 6 is a view of the mercury switch in the low water level position.

DESCRIPTION OF THE INVENTION Although the disclosure herein is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures.

The humidifier of this invention includes an evaporator pan 10 which is adapted to be mounted in a plenum chamber for a furnace and includes a heating element 12. A control assembly 14 is mounted at a point remote from the furnace and includes a reservoir 16 which is mounted at the same level as the evaporator pan 10. The control assembly maintains the level of the water in the reservoir at a predetermined level and disables the heating element 12 when the water in the evaporating pan drops below the heating element.

Means are provided for mounting the evaporating pan 10 at any angle in the plenum. Such means is in the form of a mounting plate 15 which can be readily connected to either side of the evaporating pan 10 or to the end of the evaporating pan. The mounting plate 15 can be secured to the evaporating pan 10 by any appropriate means such as welding or riveting.

Water is supplied to the humidifier from a common water source 18 connected to the reservoir by a first conduit 20 and to the evaporator pan 10 by a second conduit 22 connected between the reservoir 16 and the evaporating pan 10. Water that enters the reservoir 16 is free to flow through conduit 22 to the evaporating pan 10. The water level in the evaporating pan 10 will always be substantially the same as the water level in the reservoir 16. The flow of water to the reservoir 16 is controlled by means of an electrically actuated solenoid 24 which is normally closed.

Means are provided for indicating the water level in the reservoir 16 in the form of a float 26 mounted on a rod 28. 7

Float 26 can be made of any buoyant material such as foamed plastic. The rod 28 is pivotally connected by means of a pivot pin 32 to a pair of brackets 30 secured to the reservoir 16.

In accordance with the invention, means are provided on the float 26 for controlling the solenoid valve 24 and for disabling the heating element 12. Such means is in the form of a double throw mercury switch 34 which is mounted on the float 26 and includes a generally horizontally disposed tube 36 mounted on a post 38. A first set of contacts 42 are provided at the other end of the tube 36. One or the other sets of contacts 40 and 42 will be closed by a drop of mercury 44 which is free to move from one end of the tube 36 to the other end depending on the angular position of the float 26.

Water is supplied to the reservoir whenever the water level reaches a predetermined low water level by opening the solenoid valve 24 which is connected to the contacts 40 in the mercury switch 34. More particularly, the water control valve 24 and the contacts 40 are connected in series across electric lines G (ground) and H (hot line) from an electric power mined high water level moving the float upward high enough to cause the drop of mercury 44 to move to the left in the tube 36 as seen in FIG. 2. This opens the circuit across contacts 40 de-energizing the solenoid valve 24 and closing the water line Means are provided for protecting the heating element 12 from overheating whenever the water level in the evaporating pan 10 drops below a predetermined low water level. Such means includes the electric contacts 42 which are connected in series with a relay switch 56 and the secondary winding 57 of a transformer 58 by electric lines 60, 62 and 64. The primary winding 59 of the transformer 58 is connected across the electric lines G (ground) and H (hot line) by lines 66 and 68.

The transformer 58 is used to provide a low current circuit for the relay which is normally energized to close switch 56. The relay switch 56 is connected in series with the heating element 12 and across the electric lines G and H, by lines 52 and 54.

The heating element 12 is normally energized whenever the fan motor for the furnace is energized by means of a switch 70 provided in the electric line l-l which is connected to control the primary circuit 59 for the transformer 58. The switch 70 is closed whenever the fan motor is energized so that the heating element 12 is energized whenever the furnace fan is operating.

The rate of evaporation of water is controlled by means of an adjustment cycling timer bimetal switch 74 provided in line 54. This type of a switch is normally controlled by a cam to vary the time intervals of operation and can be locked on to energize the heating element 12 whenever the fan motor switch 70 is closed.

It should be noted that the electric circuit has been adapted for use as a plug in type unit for use with a 115 V supply. The hot line has been divided into a first circuit or hot line H, and a second circuit or hot line H The primary winding 59 for the transformer 58 is connected across the ground G and first circuit H and is controlled by the fan switch 70 so that heating element 12 cannot be energized unless the fan motor switch 70 is closed. The solenoid valve 24 is connected across the ground line G and second current circuit or hot line H, and is therefore operated independently of the heating element. The solenoid valve can be opened whenever the water level in the reservoir is too low.

Means can also be provided for controlling the heating element 12 in response to humidity. Such means is in the form of a conventional humidity controlled switch 72 provided in the low current circuit line 60. If this switch is open, the relay switch 56'will be opened.

Water noise caused by the flow of water to the reservoir and water hammer caused by the closing of solenoid valve 24 can be reduced by using a restricted conduit in place of conduit 20. A slow steady flow of water will be allowed to enter the reservoir without the normal water noise generally heard when water under pressure is admitted into an open pan. In the alternate embodiment of the invention shown in FIGS. 4, and 6, the reservoir pan has been eliminated and the solenoid 24 connected directly to the evaporator pan by means of the conduit 20. The water level in the evaporator pan is maintained between predetermined limits by means of a water level sensor 80 which is mounted on the mounting plate 15. The signal from the water level sensor 80 is used to control the mercury switch 34 by means of a solenoid 82 mechanically linked to the mercury switch 34.

In this last regard, the solenoid 81 includes a coil 83 and an armature 94. The armature 94 is connected to the mercury switch 34 by means of a linkage 84 which includes a bell crank 86 pivotally mounted on a fixed pin 88 and having one leg connected to the mercury switch 34. An L bracket 90 is pivotally connected to the other leg of bell crank 86 by a pin 92 and to the armature 94 of the solenoid 82. The armature 94 is biased by means of a spring 96 to pivot the mercury switch 34 to the low water level position. Although a mercury switch is shown, the circuit of this embodiment could also be controlled by means of a double throw double pole switch.

The water level sensor 80 includes a high water level contact 97 connected to the solenoid coil 83 by a line 98 and a low water level contact 99 connected to the solenoid coil 83 by a line 100. A ground contact 101 is connected to ground by a line 102. 1 The circuit through the solenoid coil 83 is completed by a line 104 connected to the line 50.

it should be noted that the evaporator coil 12 in this embodiment of the invention is embedded within the base of the evaporator pan 10 so that it will not be afiected by the deposit of calcium in the pan due to evaporation of the water.

in operation, when the water level in the evaporator pan 10 drops below the ground contact 101, the circuit to the solenoid coil 83 will be opened and the armature 94 will be biased outward from the solenoid coil 83 by means of the spring 96 tilting the mercury switch 34 to the position shown in FIG. 6. The drop of mercury 44 will close the circuit across contacts 40, energizing the water control valve solenoid 24 and opening the valve to allow water to flow into the evaporator pan through conduit 20. The water will rise in the evaporator pan 10 until it covers the ground contact 101 and the high water level contact 97. The water will initially complete the circuit across the low water level contact 99 and the ground contact 101 energizing the solenoid coil 83. However, the force of the coil 83 will not be sufiicient to pull the armature 94 into the coil 83 due to the bias of the spring 96. When the water completes the circuit from the ground contact 101 to the high water level contact 97, the force of the coil will then be sufficient to pull the armature 94 into the coil 83. The mercury switch 34 will be tilted to the position shown in FIG. 5 opening the circuit across contact 40 and de-energizing the solenoid valve 24. The flow of water into the evaporator pan will then stop. The drop of mercury 44 will close the circuit across contacts 42 energizing the low current circuit through lines 60 and 62 to the solenoid switch 56.

As the water evaporates, the circuit across high water contact 97 and the ground contact 101 will again open. The circuit across the ground contact 101 and the low water level contact 99 will remain closed, providing sufficient energy to the solenoid coil 83 to hold the armature 94 within the coil until the water drops below the ground contact 101. When the water drops below the ground contact 101, both circuits to the solenoid coil 83 will be opened and the armature 84 will drop due to the spring 96 opening the low current circuit and again closing the circuit to the solenoid. In the preferred embodiment, approximately a /2 inch water level difference is provided by means of the location of the high. and low water level contacts. The primary advantage of this embodiment of the invention is the ability to put the control mechanism at any position with respect to the evaporator pan. That is, it is no longer necessary to mount the control at the same level as the evaporator pan.

Various of the features of this invention are set forth in the following claims:

I claim:

1. A humidifier for a central hot air system having a plenum chamber, said humidifier comprising, an evaporator pan mounted in the plenum chamber, a reservoir amounted at the same level as said evaporator pan, a conduit connecting said reservoir to said evaporator pan, means including a solenoid valve connecting said reservoir to a source of water, a float mounted to respond to the level of water in said reservoir, a mercury switch mounted on said float and electrically connected to said solenoid valve to energize and open said solenoid valve when the water level in the reservoir drops below a predetermined low water level and to de-energize and close said solenoid valve when the water in said reservoir reaches a predetermined high level.

2. A humidifier adapted to be connected to an electric power source and mounted in a plenum chamber for a hot air heating system, said humidifier comprising an evaporator pan, means for mounting said pan in the plenum of the furnace, means for evaporating water in said pan, a reservoir mounted at a point remote from said pan and at substantially the same level, a conduit having a restricted orifice connecting said reservoir to said evaporating pan, means including an electrically actuated solenoid valve for supplying water to said reservoir, and means responsive to the level of water in said reservoir for controlling said supplying means, said controlling means including mercury switch having a first set of contacts connected to an electric power source and to said solenoid valve to energize said solenoid valve whenever the water in the reservoir drops below a predetermined minimum and to deenergize said solenoid valve when the water reaches a predetermined high water level and a second set of contacts connected to the electric power source and to said evaporating means to disable said evaporating means when the water level in the reservoir drops below a predetermined low water level.

3. The humidifier according to claim 2 wherein said 5, The humidifier according to claim 2 including a first electric circuit connecting said primary winding to the electric power source and a second circuit connecting said solenoid valve to the electric power source whereby said solenoid valve is actuated independent of said evaporating means.

6. A humidifier for a central hot air heating system having a plenum chamber, said humidifier comprising an evaporator pan positioned in said plenum chamber,

electric means for sensing high and low water levels in said an electric heater positioned to evaporate water in said pan,

means including a solenoid valve for supplying water to said evaporator pan,

a switch having a first set of contacts connected to power source for controlling said solenoid valve and a second set of contacts for controlling said heater, linkage means for actuating said switch, means including an armature operatively connected to said linkage means and a coil electrically connected to said sensing means for actuating said switch, I

a transformer having a primary winding connected to the electrical power source independent of said first set of contacts, and a secondary winding, an electrically actuated relay switch connected to control said heating element and a low current circuit connected to said secondary winding, relay switch and second set of contacts whereby when said water reaches a predetermined low level, said coil will be de-energized and said armature will move said switch to a position to close said first set of contacts and energize said solenoid valve to supply water to said pan and open said second set of contacts to de-energize said heater, and when said water in said pan reaches a. predetermined high level, said coil will be energized and said armature will move said switch to a position to open said first set of contacts and deenergize said solenoid valve and close said second set of contacts to energize said relay switch.

7. The humidifier according to claim 6 wherein said switch comprises a mercury switch.

8. The humidifier according to claim 6 wherein said switch actuating means comprises a second solenoid. 

1. A humidifier for a central hot air system having a plenum chamber, said humidifier comprising, an evaporator pan mounted in the plenum chamber, a reservoir amounted at the same level as said evaporator pan, a conduit connecting sAid reservoir to said evaporator pan, means including a solenoid valve connecting said reservoir to a source of water, a float mounted to respond to the level of water in said reservoir, a mercury switch mounted on said float and electrically connected to said solenoid valve to energize and open said solenoid valve when the water level in the reservoir drops below a predetermined low water level and to deenergize and close said solenoid valve when the water in said reservoir reaches a predetermined high level.
 2. A humidifier adapted to be connected to an electric power source and mounted in a plenum chamber for a hot air heating system, said humidifier comprising an evaporator pan, means for mounting said pan in the plenum of the furnace, means for evaporating water in said pan, a reservoir mounted at a point remote from said pan and at substantially the same level, a conduit having a restricted orifice connecting said reservoir to said evaporating pan, means including an electrically actuated solenoid valve for supplying water to said reservoir, and means responsive to the level of water in said reservoir for controlling said supplying means, said controlling means including mercury switch having a first set of contacts connected to an electric power source and to said solenoid valve to energize said solenoid valve whenever the water in the reservoir drops below a predetermined minimum and to deenergize said solenoid valve when the water reaches a predetermined high water level and a second set of contacts connected to the electric power source and to said evaporating means to disable said evaporating means when the water level in the reservoir drops below a predetermined low water level.
 3. The humidifier according to claim 2 wherein said evaporating means comprises a heating element in the bottom of said evaporator pan.
 4. The humidifier according to claim 2 including a transformer having a primary winding connected to the electric power source independently of said first set of contacts and a secondary winding connected to said second set of contacts, and an electrically actuated relay switch connected to control said heating element and controlled by said secondary winding.
 5. The humidifier according to claim 2 including a first electric circuit connecting said primary winding to the electric power source and a second circuit connecting said solenoid valve to the electric power source whereby said solenoid valve is actuated independent of said evaporating means.
 6. A humidifier for a central hot air heating system having a plenum chamber, said humidifier comprising an evaporator pan positioned in said plenum chamber, electric means for sensing high and low water levels in said pan, an electric heater positioned to evaporate water in said pan, means including a solenoid valve for supplying water to said evaporator pan, a switch having a first set of contacts connected to power source for controlling said solenoid valve and a second set of contacts for controlling said heater, linkage means for actuating said switch, means including an armature operatively connected to said linkage means and a coil electrically connected to said sensing means for actuating said switch, a transformer having a primary winding connected to the electrical power source independent of said first set of contacts, and a secondary winding, an electrically actuated relay switch connected to control said heating element and a low current circuit connected to said secondary winding, relay switch and second set of contacts whereby when said water reaches a predetermined low level, said coil will be de-energized and said armature will move said switch to a position to close said first set of contacts and energize said solenoid valve to supply water to said pan and open said second set of contacts to de-energize said heater, and when said water in said pan reaches a predetermined high level, said coil will be energized and said armature will move said switch to a position to open said first set of contacts and deenergize said solenoid valve and close said second set of contacts to energize said relay switch.
 7. The humidifier according to claim 6 wherein said switch comprises a mercury switch.
 8. The humidifier according to claim 6 wherein said switch actuating means comprises a second solenoid. 